Inclusion criteria will consist of affected individuals with unilateral or bilateral microphthalmia/anophthalmia from families with an X-linked mode of transmission. In addition, we may analyze patients with mental retardation with or without eye defects to allow genotype phenotype correlation studies. Parents and siblings will be included for linkage analysis. Unaffected non-transmitting parents may be included to clarify haplotype status. In addition, families with X-linked microphthalmia/anophthalmia with associated anomalies such as Lenz dysplasia and other X-linked microphthalmia/anophthalmia syndromes will be analyzed to determine if these conditions are allelic. Sporadic cases of microphthalmia with or without mental retardation may be considered for study, along with parents and unaffected siblings. Unaffected subjects may also be enrolled if needed for controls.